Unfortunately, @react-native-community/blur is partly native code. For a react-native module that depends on some native code to work in the Expo managed workflow, the native code needs to be built into Expo’s SDK.
The native code for expo-blur is included in the Expo SDK, but not the native code required by @react-native-community/blur.
So if you want to use it, you will unfortunately need to eject.
In future when the Managed Workflow support for EAS has been released, it should be possible to use things like @react-native-community/blur, but until then you’ll have to eject to the Bare Workflow.